1. Field of the Invention
The present invention relates to a method and apparatus for determining the point of impact and average velocity of a projectile on a screen. In particular, the present invention has utility in machines and systems that simulate sports games and, especially, games that desire determination of the flight of the projectile. Such a sports game, for example, is a golf simulation game.
Such golf simulation games are generally known and are usually of the size that fit indoors, namely within a premises. These simulation games provide a tee area, a target area and, in some instances, a putting area. The player tees off in a normal manner and his drive is measured and relayed in yardage of unemployed travel to simulate a drive on an actual golf course. The simulation is accomplished by appropriate controls that receive signals from a specially designed screen which is impacted by the golf ball.
The present invention concerns a system for accurately determining the point on the screen which is impacted by the driven projectile, such as a golf ball. With the determination of the point of impact in relation to the golf tee or the start point from which the projectile began its flight, suitable calculations can be made to determine the projectile's trajectory and velocity.
2. Description of the Prior Art
The prior art includes golf simulating machines of the general types shown in U.S. Pat. Nos. 3,508,440 to Murphy and 3,712,624 to Conklin. These patents attempt to simulate a golf game and include tee areas, screens to receive a driven ball and systems to determine flight characteristics or trajectory of the ball. A problem in the past has been that of accurately determining the characteristic of the ball's trajectory.
The U.S. Pat. Nos. 2,331,236 and 2,331,237 to Schaeffer relate to a golf practice screen employing acoustics but rely upon an arrangement in which the intensity of the sound created by the ball impacting the screen is a function of the velocity. The system of these patents register the intensity of the ball impacting the screen. Unlike these Schaeffer patents, the present invention calculates time difference of the first arrival of the acoustical wave at various strategic sound wave detection device locations to determine the point of impact.
Other prior patents include U.S. Pat. No. 4,009,883 to Yeilowlees which produces an impact intensity signal from a microphone which is converted to a meter reading of an impact. Also, U.S. Pat. No. 2,784,006 to Semjian which provides frequency tuned strips to indicate the location of impact. Further, U.S. Pat. No. 2,012,166 to Roberts measures velocity with the purpose of teaching a consistent swing tempo to the player.
The present invention, unlike the prior art, relies on a unique acoustical arrangement that through the measurement of time differentials and an appropriate algorithm locates the point of impact of the ball on the screen.